In an experiment, a charge of −300μC is moved from point A to point B in an external electric circuit. The potential at B is 15 V higher than at A.
a. (i) What does the negative sign of the charge signify?
b. (ii) Determine the work done in moving the charge from A to B. Express your answer in millijoules.
c. (iii) State whether the work done by the external agent is positive, negative, or zero, and justify your answer on the basis of your calculation.